PI Controller Gain Adjustment for Steam Generator Level Control
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Solution Overview
Problem
Nuclear power plants face challenges in controlling the level of main feed-water in steam generators during reactor power transfers between low and high power sections, leading to excessive feed-water levels that can cause reactor stoppages and operational burdens.
Innovation Solution
A method that adjusts the gain and integral time constant of a proportional-integral (PI) controller using an information transformer, providing transformed PI information for a predetermined timer period during power section transfers, to manage the main feed-water control valves and prevent excessive feed-water levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the main feed-water control valves are transferred between low and high power sections, then the reactor power can be adjusted between different operating ranges, but excessive feed-water level occurs in the steam generator causing operational problems
Solution Approach 1:
The control system dynamically adjusts the PI controller parameters (gain and integral time constant) based on the current operating power section. When transitioning between low and high power sections, the system automatically selects appropriate controller parameters to maintain stable feed-water level control, preventing excessive level variations that would otherwise occur during power adjustments.
Solution Approach 2:
The invention changes the control parameters of the PI controller according to the reactor power section. By transforming the gain and integral time constant values based on the current power level, the system adapts the control characteristics to match the plant's dynamic behavior at different operating points, thereby maintaining reliable level control during power transfers.
2Device complexity
If fixed PI controller parameters are used during power transfers, then the control system is simple to implement, but excessive steam generator levels occur causing reactor stoppages
Solution Approach 1:
The control system transitions from fixed parameters to dynamic parameter adjustment based on power section. The PI controller automatically transforms its gain and integral time constant values according to the current operating power level, enabling the system to adapt to changing plant dynamics during power transfers without requiring complex manual intervention or causing operational stoppages.
3Reliability
If manual intervention is used to control feed-water levels during power transfers, then excessive levels can be prevented, but operational burden on personnel increases
Solution Approach 1:
The control system performs self-adjustment by automatically transforming the PI controller parameters based on the detected power section. The system monitors the reactor power level and autonomously modifies the control parameters to maintain stable feed-water levels during power transfers, eliminating the need for manual operator intervention and reducing operational burden while maintaining reliable control.
Data Source
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AI summary
A system and a method of transforming a gain and an integral time constant of a proportional-integral (PI) controller according to a timer lapse time to relieve an excessive phenomenon of a steam generator level caused by rapid changes in open degrees of a downcomer feed-water valve and an economizer feed-water valve when reactor power transfers between low and high power sections. Accordingly, an excessive phenomenon of a steam generator level is relieved at a transfer time when reactor power transfers between low and high power sections. Therefore, a possibility of a stop of a reactor caused by the excessive phenomenon of the steam generator level is reduced to relieve burden on an operator and improve an operation rate and economic feasibility of a nuclear power plant.